Amp Biasing Meter

Discussion in 'Amps and Cabs' started by kc_hubbs, Apr 15, 2015.

  1. kc_hubbs

    kc_hubbs Member

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    I was looking in to getting a biasing meter or just a few probes that connect to a regular volt meter.

    Can you guys offer any advice ?

    The one i mainly looking at is going to run me $200. Its a Quad-tube meter by asharpfretworks. It would allow me to hook up 4 power tubes at one and be able to select any tube and view the current, and the plate voltage.

    I didnt know if this was overkill, or if something that would make things a little easier.

    Also, i could just pick up a couple bias probes that connect to the tube, and to a volt meter. Would be a lot cheaper but would only allow me to test one tube at a time.

    I have 2 amp heads that i would like to be able to take care of, as well as a few friends who i would be doing it for. Nothing professional, or

    Does anyone here have any set up to bias there own amps ?
     
  2. Silent Sound

    Silent Sound Member

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    Just get a probe and a decent digital multimeter. A good digital multimeter is something that you can use for all kinds of situations other than just biasing tubes. Also, why would you need to measure 4 tubes at once? You don't bias your tube amps every day. So the time you would save doing all four at once versus each one individually isn't worth worrying about. Does your amp even have separate adjustments for each power tube anyway? Lastly, I'd trust any Fluke DMM over even a $200 bias probe for accuracy.
     
  3. kc_hubbs

    kc_hubbs Member

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    I have tons of multimeters around here, I have one Fluke. I work in the industrial electrical field. Thats one thing i kept coming back to was the reliability of a tube meter compared to a professional multimeter.

    The amps just have a single bias adjustment. I read that you should always adjust your bias off the tube that has the highest current draw, so i figured having all 4 tubes hooked up would be easier.
     
  4. swiveltung

    swiveltung Member

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    You say you have heads... keep in mind that some setups wont allow you room to plug the power tube in to the probe socket due to the vertical head space. Some bias probe makers sell right angle plugs so you don't have to remove the chassis every time.
    BTW: there was a Weber Bias Rite on the emporium a short time back....

    I used to do it with a meter but am VERY glad I bought a probe. I can check plate voltage and bias on either tube with a flip of a switch. It's handy for sure.
     
  5. logdrum

    logdrum Member

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    It needs a bit of soldering but this is what I use.

    https://www.tubedepot.com/products/tubedepot-bias-scout-kit

    I made 2 of them for 20 each and Harbor Freight gave me 2 cheap DMMs (they are also 5 bucks each) that I permanently attach to these. I also have a Fluke DMM and the cheapo Harbor Freight ones measured close to what the Fluke says.

    50 vs 200 was a no-brainer to me.
     
  6. jcs

    jcs Member

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    I use the Weber bias rite but ALWAYS get the plate volt option.

    This displays the plate volts at a flip of the switch.

    MUCH better than probing around in a live amp.

    Another cool thing with the plate volt option is you can quickly calculate total power & you will quickly see the difference in plate volts with different rectifiers.
     
  7. NAC25

    NAC25 Supporting Member

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  8. Mike9

    Mike9 Supporting Member

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    Amp Head dual bias tester here - hooks up to any DMM and works great.
     
  9. RG955TT

    RG955TT Member

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    Bluewail likes this.
  10. Trotter

    Trotter Supporting Member

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    I've had great luck with the Weber Bias Rite.

    The Compubias looks like an excellent tool as well
     
  11. Xlch721

    Xlch721 Member

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    I use this one The Eurotubes "Pro One" Bias Probe
    https://www.eurotubes.com/store/pc/bias%20probes.htm
    Works great for the money but it only tests one tube at a time so you have to power down the amp for a minute or so to swap it out to the other side but it does work great for Octal Tubes but they have one for 9 pin tubes like an EL84 ect
    I use it on my DRRI and several friends amps when its time to retube them. Gonna use it when I fire up my Plexi build hopefully this weekend if everything shows up like its supposed to.
     
  12. Sean French

    Sean French Supporting Member

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    Bias Rite with the plate volt option is what I use. :aok
     
  13. kc_hubbs

    kc_hubbs Member

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    The eurotube probe seems to be the one to go for. I figured i could buy a prob and a cheap meter every few weeks then i could view all 4 power tubes at once. For now, having one prob would be good enough.
     
  14. lovebigrigs

    lovebigrigs Member

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    amp-head makes an awesome one!
     

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